This excellent piece orginally appeared at Badlands Fieldcraft. -NCS
I recently acquired a new precision rifle system and I wanted to get it “up and running” so to speak. This involves finding a load the rifle likes, mounting optics and accessories and then determining the ballistics for this combination of rifle and ammo to get a reliable and repeatable system.
Although I can hand load and have developed many sub-MOA loadings for quite a few rifles, it’s a time consuming task and I’d rather spend the money on good ammo and spend the time on training. I chose to go with a factory match loading from Hornady for this rifle and it produces sub-MOA groups right out of the box. Good enough for me since I’m really only concerned with sub-MOM (Minute of Man) accuracy.
So with the equipment side of things handled, its time to start developing the “D.O.P.E.” for this particular rifle and ammo combination. Traditionally this was done through meticulous recording of the results and conditions of every round fired to eventually develop an overview of what to expect under similar firing situations.
While I’m a big fan of trying to keep things as low tech as possible, there’s also no reason to ignore a useful tool when it’s available. Rather than keep a specific data book, I utilize a ballistic calculator on my phone until I have developed the data enough to create ballistic tables for “off grid” use.
There are many advantages to this over the traditional route, including the fact that it’s quicker and uses less ammunition. It also produces a more accurate product in the end that is then able to be replicated over different atmospheric conditions more accurately.
The farther you need to shoot there are more variables that need to be taken into account, and I wanted to have solid and proven ballistic data for this rifle. While there are some good ballistic calculators that can get you close just by putting in the factors that you know out of the box, going out and shooting at distance will get you corrected data so that you can “true” your ballistic calculator.
During this process I’ll be using an IPhone ballistic calculator app called “StrelokPro”. While this isn’t a review of the app itself, I have used it extensively on multiple rifles and it has helped me to develop solid analog (off-grid) rifle data. That should be the goal when using electronics, use them to help you get to a point where you don’t need them anymore. In addition to the app I also take notes on every shooting session so if my phone should get destroyed or lost I still have all the data. Additionally I print a ballistics table from within the app with all the pertinent data on it as well.
The rifle is a Ruger American Predator in 6.5 Creedmoor. Thus far I’ve got about 50 rounds down the pipe and she’s a shooter to say the least. I’ve recently installed a Silencerco Saker Brake/ Suppressor Mount and I need to rezero the rifle since adding the mount will affect the barrel harmonics and throw off my zero.
The day starts me out with a bore sighted rifle. When I get to the range I take out all the ammo and my rifle and set them up in the Sun to warm up. It only takes me about 5 minutes to get to the range from my house and all my equipment is still cool from being inside. This is important because the temperature of your powder has a large effect on the velocity of your rounds. When you’re recording the air temperature in your ballistic calculator it’s assumed your rounds are the same temp, if not you won’t have repeatable results when you’re done.
I put in the temperature, humidity and barometric pressure into the ballistic app to get started and after letting my ammo warm for about 10 minutes I start off firing prone with a bipod at 100 yards. It takes me two 3 round groups to get the rifle zeroed at 100 yards. I slip the turrets to set them back to “0”, then install my suppressor and fire three more rounds. Since I’ve already marked my previous hits, these three new holes will be obvious. I go down range and measure to the centerline of this new group and get about 3.25” down from where I was aiming. I’ve aimed at the same place on the target for all my shots. This 3.25” is a rough measurement for my zero shift with my suppressor.
Next I take the target out to 425 yards. I check the ballistic app for the predicted elevation and windage settings and I fire three rounds unsuppressed, then go check the target. The group is just under 1 MOA and about 1/4 MOA high on elevation but I didn’t hold enough for wind so I’m about 4 inches left. I’m using an IPSC silhouette target and this group still has one “A” and two “C’s”. Not too big of a deal there, I really wanted to make sure my elevation was good since it’s come from my ballistic calculator and hasn’t been trued yet. The app itself has a Truing section, so I tell it to add another .25 MOA at 425 yards and it recalculates the ballistic curve of the round. It can do this two ways, either by adjusting the entered muzzle velocity or the ballistic coefficient. Since I don’t have a chronograph with I just let it adjust the muzzle velocity.
I return to the rifle, install the suppressor, then fire three more rounds. In between all my groups I leave the bolt open both as a safety courtesy to other shooters should they arrive but also to help cool my rifle between firing.
This next group is a bit larger than one MOA and this time I’ve held too much for wind, being about 3 inches right. This group also centers about 3.25 MOA low so it’s pretty safe to say my zero shift is 3.25 MOA. I record all this information in my notebook, take a picture of the target for future reference than pack up my gear. I load up and head to a friends house to do some more shooting.
I arrive at my friends house a bit later. The first range I was at only goes out to 425 yards, but my friend has steel at 600 yards and also a 1000 yard steel target. I pull up to the house and he loads his gear in my pickup and we drive to the firing position. It’s about 90 degrees out and luckily there is only a small breeze, enough to cool us off but not make shooting too difficult.
We had discussed gathering data earlier and he is graciously going to let me borrow his chronograph so I can get more accurate data for my rifle. Friends in high places indeed.
I bring up my ballistic app, ensuring the atmospherics are good and it shows me the firing solution for the 600 yard target. The wind is coming from our 5 o’ clock and is gusting from 0-10 MPH.
I proceed to fire six rounds, adjusting slightly left and right as I feel the wind change. All six times I’m greeted with a nice “gong” sound as my bullets impact the heavy steel targets. I’m also happy to have a solid velocity with which to put into my app.
2677 Feet per second is my new number. I change it in the app and then put my previous dope back in to true it again. This time I’ve added my dope under the BC truing instead of muzzle velocity. From now on all truing will be done here.
After my friend annihilates the 600 yard target it’s time to try for the 1000 yard target. I once again go to the app for the predicted firing solution and begin firing. My first round kicks up dust way high of the target, about 3 MOA according to the measurement in my reticle. It felt like a solid shot but I decide to fire another just to be sure. Once again dust kicks up in nearly the same spot. I dial down 3 MOA on my turrets and fire again. At first I think I’ve missed, but then after about a second I’m greeted with the lovely “gong” sound again. I proceed to engage the target three more times using these sight settings. Once I’m satisfied I go back in the app and input the new settings for 1000 yards. It adjusts the BC once more so now I will confirm it at 600 again.
I adjust the app for 600 yards and notice that the elevation is the same as I previously had used. I engage the target three times with three “gongs” returned. I’m highly satisfied with the results of this afternoons shooting, walking away with trued ballistic data out to 1000 yards and having more than proven myself and rifle system capable of shooting at those distances.
While I have a very solid start I would like to repeat the process in cooler weather to gain more muzzle velocity data to put into my ballistic calculator to help refine it further. There will be a bit more refining to do until I’m happy with everything but I feel this system is well on its way should it be needed soon.